code: def test_weave_alkane():
      """Test on simple alkane"""
      mols = ["CCC"]
      featurizer = dc.feat.WeaveFeaturizer()
      mol_list = featurizer.featurize(mols)
      mol = mol_list[0]
  
      # 3 carbonds in alkane
      assert mol.get_num_atoms() == 3
  
      # Test feature sizes
      assert mol.get_num_features() == 75
  
      # Should be a 3x3 interaction grid
      assert mol.get_pair_features().shape == (3 * 3, 14)
  
file_path: deepchem/deepchem/feat/tests/test_weave.py
imports: import numpy
  import deepchem
  from deepchem.feat.graph_features import max_pair_distance_pairs
label_desc: Use image node_id 5 for calling a global function with example usage: test_weave_alkane() without return types